# Lightning protection of a private house with detached high-rise lightning rods

Usually single-family houses are protected by lightning rods, located on their roofs. But sometimes customers do not want to install any additional elements on the building , in order not to change its exterior. In such cases it is possible to protect the house from atmospheric discharges by detached lightning rods. If the building is two- or three-storeyed, then in order to guarantee reliable protection, the interception rod must be sufficiently high. Recently, the ZANDZ Technical Center was given the task to calculate lightning protection of a single-family house 11 m high without installing lighting rods on it. We proposed a solution using air-terminals masts located at a distance from the house. Let's study it in more detail.

## An example of a single-family house lightning protection

Object: single-family house.

Figure 1 - Plan of the object.

Task: Perform calculations of the lightning protection system of a private house using detached lightning rods.

The protection of buildings and structures against lightning discharges is ensured by lightning rods. A lightning rod is a device rising above the facility that diverts lightning current into the ground without entering the facility. It consists of a lightning rod which directly takes the lightning discharge upon itself, a down conductor and a ground electrode.

Solutions to meet the requirements for a private house lightning protection system:

1. Lightning protection is carried out in accordance with IS 153-34.21., 122-2003"Instructions for lightning protection of buildings, structures and industrial communications" (hereinafter IS) and 34.21.122-87 "Instructions for lightning protection of buildings and structures" (hereinafter AD).

2. The object refers to category 3 of lightning protection. System reliability must be not less than 0,9.

3. The lightning protection of the object is made with the help of 2 vertical detached air-terminal masts 14 m high (ZZ-201-014).

4. Installation of a grounding device for each mast, consisting of 2 vertical electrodes with a length of 3 m, connected by a horizontal electrode (copper bonded tape of 30x4 mm). The distance from the horizontal electrode to the foundation of the building is not less than 1 m, the depth is 0.5 - 0.7 meters;

Results of the calculation carried out with the software developed by the JSC "Energy Institute to the name of G.M. Krzhizhanovsky (JSC "ENIN"):

The density of lightning discharges into the ground – 4 strikes / sq. km per year

The total number of strikes into the system is 0.032 (once every 31 years);

The total number of breakthroughs is 0.0013 (once in 769 years);

System reliability - 0,958.

Probability of breakthroughs into all the system objects - 0.042.

Figure 2 shows the arrangement of equipment.

Table 1 gives the list of the required equipment and materials.

Figure 2 - Location of equipment for lightning protection of a single-family house.

Условные обозначения - notations
Молниеприемник мачта высотой 14 м – air-terminal mast 14 m high
Электрод - electrode
Полоса омедненная стальная сечением 30 на 4 – copper-bonded tape with the cross-section of 30 to 4

Table 1 - List of need in materials.

 № Figure Product item Name Quantity, pcs. 1. ZZ-201-014 ZANDZ Vertical lightning rod 14 m (galvanized steel; with embedded fittings for placing under the foundation) 2 2. ZZ-001-065 ZANDZ Copper-coated threaded grounding rod (D14; 1.5 m) 8 3. ZZ-002-061 ZANDZ Threaded coupler 5 4. ZZ-003-061 ZANDZ Starting tip 4 5. ZZ-004-060 ZANDZ Driving head for a jackhammer 2 6. ZZ-006-000 ZANDZ Conductive grease 1 7. ZZ-008-000 ZANDZ Header for a jackhammer (SDS max) 1 8. ZZ-005-064 ZANDZ Clamp for connecting conductors (up to 40 mm) 8 9. ZZ-007-030 ZANDZ Waterproof tape 2 10 GL-11075-20 GALMAR Copper-bonded tape (30 * 4 mm / S 120 mm²; coil of 20 meters) 1